As one component of the "NIH/DC Initiative to Reduce Infant Mortality" a program of research addressing the threat of injuries and neglect to infants and toddlers in the District of Columbia has been developed. A comprehensive, city-wide injury surveillance system was established which collected data about injuries in children <3 years of age that resulted in an emergency room visit, hospitalization or death. Information about substantiated cases of abuse and neglect was also obtained from the Department of Family Services. Data collection is complete. Preliminary figures on accrual rates are available for all ten study hospitals. For the one year period from October 1, 1995 through September 30, 1996, 3039 injury-related visits were identified yielding an annual event-based rate of 13.5/100 persons/year. There were 9 deaths, 163 hospitalizations, and 2,867 emergency department visits. Injury rates were highest in 1-2 year olds and lowest in infants. Leading causes of injury varied with severity. Intentional injuries and injuries where intent was undertermined by suspicious of being intentional comprised the largest fraction of deaths (n=4, 44%) and hospitalizations (n=36, 22%). In contrast intentional injuries and injuries of undertermined intent accounted for only 2% of ED visits (n=56). Forty-two percent of injury-related ED visits were for falls (n=1245). At three of the study sites a questionnaire was administered to the parent or care giver shortly after the injury event. Of the 1913 families who were leigible for an interview, 1,445 (77%) were contacted and interviews were completed for 1,352 (93% of contacts). A manuscript reporting parental sensitivities to the interview was published in Injury Prevention. This study provides one of the first in-depth looks at non-fatal injuries in infants and toddlers. In addition, it demonstrates that multi-hospital surveillance is feasible and can provide population-based estimates of injury risk, thus identifying leading causes and high risk neighborhoods for targeted interventions. Current efforts are focused on the preparation of manuscripts for peer review.